chore(deploy): rework k8s pipeline, monitoring and postgres 17

Deploy workflow uses git-tracked manifests, DISABLED flag and kustomize overlays; add webinar-checker metrics with ServiceMonitor and alerts; upgrade shared postgres to 17 with statuspage DB and probes/resources.

edu_master/k8s/service.yaml

@@ -0,0 +1,15 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: webinar-checker
+  namespace: edu-master
+  labels:
+    app: edu-master-webinar-checker
+spec:
+  selector:
+    app: edu-master-webinar-checker
+  ports:
+    - name: metrics
+      port: 8000
+      targetPort: metrics
+      protocol: TCP